Olayinka S. Ohunakin

ECONOMIC ANALYSIS OF WIND ENERGY CONVERSION SYSTEMS USING LEVELIZED COST OF ELECTRICITY AND PRESENT VALUE COST METHODS IN NIGERIA

Technical electricity generation assessment and economic analysis of six wind energy conversion systems in the categories small, medium, and large (with power ratings of 20, 35, 275, 500, 1,000, and 2,000 kW) were examined in this study. Electricity cost values were estimated based on the levelized cost of electricity (LCOE) and present value cost (PVC) methods for six locations selected across all the geopolitical zones of Nigeria. This was done using wind speed data that span between 25 and 37 years, measured at the height of 10 m. The result showed that the annual average energy output ranges from 2.242 MW h in Uyo with P10-20 turbine to 12,521.55 MW h in Kano using Vestas V80-2 MW wind turbine. Furthermore, of all the selected sites, Kano gave the least costs of electricity production per kilowatt hour with Vestas V80-2 MW model at 67-m hub heights, while the highest is obtained in Uyo with GEV-HP (1 MW) model at 70-m hub heights for the LCOE and PVC height for both the LCOE and PVC methods. In addition, sensitivity of the selected parameters to the levelized cost of electricity was also carried out.

A Typical Meteorological Year Generation Based on NASA Satellite Imagery (GEOS-I) for Sokoto, Nigeria

Computer simulation of buildings and solar energy systems are being used increasingly in energy assessments and design. This paper evaluates the typical meteorological year (TMY) for Sokoto, northwest region, Nigeria, using 23-year hourly weather data including global solar radiation, dew point temperature, mean temperature, maximum temperature, minimum temperature, relative humidity, and wind speed. Filkenstein-Schafer statistical method was utilized for the creation of a TMY for the site. The persistence of mean dry bulb temperature and daily global horizontal radiation on the five candidate months were evaluated. TMY predictions were compared with the 23-year long-term average values and are found to have close agreement and can be used in building energy simulation for comparative energy efficiency study.

Economics of wind energy utilisation for water pumping and CO2 mitigation potential in Niger Delta, Nigeria

ABSTRACT The wind characteristics of six locations in Niger Delta, Nigeria, and the economics of the application of wind energy for water pumping and possible avoidable CO2 emissions through wind utilisation were examined. The wind data were measured at 10 m height and analysed using the two-parameter Weibull model. Small size wind turbines were accessed with Goulds 45J03 water pump series. The average power density, average energy density and annual energy across locations ranged between  W/m2,  kWh/m2 and  kWh/m2/year, respectively. Bergey Excel-10 kW turbine had the lowest cost of energy and water pumping cost of

Thermodynamic performance and environmental sustainability of adapted organic Rankine cycles at varying evaporator pressure

/kWh and

Exergy analysis of vapor compression refrigeration system using R450A as a replacement of R134a

/m3, respectively. The annual capacity of water yield varies from 21,847 to 120,206 m3/year on a total dynamic head of 50 m. Furthermore, the annual diesel saved across the locations ranged from 1605 to 8696 l/year (17.47 to 94.67 GJ/year), while the annual averaged CO2 saved was between 4.32 and 22.93 tons/year.

ANN approach for irreversibility analysis of vapor compression refrigeration system using R134a/LPG blend as replacement of R134a

ABSTRACT Thermodynamic performance and environmental sustainability (ES) of adapted organic Rankine cycles (ORCs) at varying evaporator pressure (EVP) are presented. The paper assesses the most sustainable ORCs at varying EVPs. The modified ORCs apart from the generic cycle include the ORC-internal heat exchanger (IHE), ORC-turbine bleeding, and ORC-turbine bleeding and regeneration. The considered performance indicators are power output (POT), overall exergy efficiency and overall exergy destruction (OED), while the ES indicators comprise waste exergy ratio (WER), exergetic sustainability index (ESI) and environmental effect factor (EEF). From the results obtained the OEF, OED and POT for the ORCs ranged between , and , respectively, at EVP of 2 and 3 MPa. Similarly, WER, ESI and EEF ranged between , and correspondingly, for the same EVPs. The findings indicate the ORC-IHE and ORC-turbine bleeding and regeneration are more sustainable using the R113 than R141b refrigerant.

A comparative study of selected multi-criteria decision-making methodologies for location selection of very large concentrated solar power plants in Nigeria

This paper experimentally investigated exergetic performance analysis of vapor compression refrigeration system using R450a as a replacement for R134a at different evaporator and condenser temperatures within controlled environmental conditions. The exergetic performance analysis of the vapor compression refrigeration system with test parameters including efficiency defects in the components, total irreversibility, and exergy efficiency of the refrigeration system was performed. Findings showed that the total irreversibility and exergy efficiency of the vapor compression refrigeration system using R450A refrigerant were lower and higher than R134a by about 15.25–27.32% and 10.07–130.93%, respectively. However, the efficiency defect in the condenser, compressor, and evaporator of the R450A refrigeration system was lower than R134a by about 16.99–26.08%, 5.03–20.11%, and 1.85–15.85%, respectively. Conversely, efficiency defect in the capillary tube of the R450A refrigeration system was higher than R134a by about 14.66–78.97% under similar operating conditions. Overall, it was found that the most efficient component was the evaporator, and the least efficient component was the compressor for both refrigerants.

Photovoltaic performance prediction in Northern Nigeria using generated typical meteorological year dataset

This paper experimentally evaluated the irreversibility in the components (compressor, condenser, capillary tube, and evaporator) of the vapor compression refrigeration system (VCRS) using R134a/LPG refrigerant as a replacement for R134a. For this aim, different tests were conducted for various evaporator and condenser temperatures under controlled surrounding conditions. The results reported that the irreversibilities in the components of VCRS using R134a/LPG blend were found lesser than irreversibilities in the components of VCRS using R134a under similar experimental conditions. Artificial neural network (ANN) models were developed to predict the second law of efficiency and total irreversibility of the refrigeration system. ANN and ANFIS model predictions were also compared with experimental results and an absolute fraction of variance in range of 0.980–0.994 and 0.951–0.977, root-mean-square error in the range of 0.1636–0.2387 and 0.2501–0.4542 and mean absolute percentage error in the range of 0.159–0.572 and 0.308–0.931%, respectively, were estimated. The outcomes suggested that ANN model shows better statistical prediction than ANFIS model.

Applications of small-scale, stand-alone wind energy conversion systems in rural Cross River State, Nigeria

This work studies the location selection of very large concentrated solar power plants (VLCSPPs) in Nigeria using five Multi-Criteria Decision Making (MCDM) methodologies including: Analytic Hierarchy Process (AHP), Consistency-Driven Pairwise Comparisons (CDPC), Decision Expert for Education (DEXi), Elimination and Choice Translating Reality (ELECTRE) III and IV. A comparative investigation is performed on only one unique model that is structured in four levels. This model has nine basic factors (Direct Normal Irradiance, grid infrastructure, climatic conditions, water availability conditions, natural disaster/hazard conditions, topographical conditions, geological conditions, land use, allocation and availability, war, terror & security conditions) taken from previous factors selection studies. There are 35 alternatives for the VLCSPP locations in Nigeria for the pre-development investment stage and are presented on Google Earth file (GE). The Super Decisions, JConcluder, DEXi and ELECTRE III-IV software are mainly used in this study. The findings show that the AHP and CDPC rankings are very close to each other. On the other hand, the DEXi, ELECTRE III and IV rankings spread very much amongst the methods. Hence, a small procedural rule is defined for the selection of candidate locations for detailed investigations. Several candidates’ VLCSPP locations were found to exist as alternatives, with approximate local central coordinates of 13°38′55.37″N, 13°20′41.41″E and 13°6′58.83″N, 13°26′53.63″E in Nigeria. These should be further investigated in the following investment stages.

Solar energy applications and development in Nigeria: Drivers and barriers

Relevant meteorological files are needed by simulation software to assess the energy performances of buildings or efficiency of renewable energy systems. This paper adopts the Sandia method to generate typical meteorological year (TMY), using a 35-year hourly measured meteorological dataset from four stations in the northern region of Nigeria. The cumulative distribution function (CDF) for each year was compared with that of the long-term composite of all the years in the period for the seven major weather indices made up of relative humidity, wind speed, minimum temperature, global solar radiation, precipitation, mean temperature and maximum temperature. The 12 typical meteorological months (TMMs) selected from the different years were used for formulation of a TMY for the zone. In addition, performance assessment of a 72-cell polycrystalline solar PV module using the generated TMY and long-term (LT) values was also conducted. Two statistical indicators, the mean percentage error and the root mean square error, were adopted to evaluate the performance of each TMY with the LT mean, and also that of the PV energy system. Findings show that the TMMs are evenly spread within the data periods across the sites while closest fit between the long-term mean and TMY are obtained with the global solar radiation followed by the mean temperature in all the sites especially in Bida and Minna. From the energy system analysis carried out, it was found that TMY data are able to predict the performance of the PV system to within 5% of the LT data.